McMinnville is on the verge of losing its low ISO rating and one ladder truck could make the difference, according to city Fire Chief Keith Martin. The city was given its current Insurance Service Office (ISO) rating of 3 in May 2008, making the city one of the highest rated communities in the state and placing it in the top 5 percent in Tennessee.How effective communities are when it comes to fighting fires is judged by an ISO rating. Departments are assigned a class from 1 to 10, with 1 representing exemplary protection and 10, the worst rating, representing no fire protection.A recent survey of the city fire department conducted by Municipal Technical Advisory Service recently scored it a 70.58, which is only .58 above the minimum qualifications to be considered ISO 3.“The only reason we made that .58 is because of the water department,” said Martin, during a city Safety Committee meeting.